1. Field of the Invention
The invention relates to a saw carrier assembly particularly adapted for, but not limited to, mounting with a feller buncher or other tree falling apparatus.
2. Prior Art
Apparatus for falling trees, such as the feller bunchers, have been used for many years and commonly include a pair of spaced grapples mounted on a post carried on a vehicle. A tree severing means, such as shears, a movable chain saw, or a movable circular saw, is mounted below the lower grapple so as to sever an upper portion of the tree from a lower portion, while concurrently supporting the upper portion of the tree. Difficulties associated with the prior art apparatus increase as the size of the tree increases. The inventor has found that friction associated with the conventional chain saw tends to limit the size of the tree that can be cut with this type of apparatus, particularly when cutting trees having butt diameters greater than 60 cm.
Means to reduce friction associated with the conventional chain saw have been tried. For example, U.S. Pat. No. 789,512 (Waller) discloses a chain saw in which a chain passes around a pair of spaced arms carrying free wheeling sheaves. However, the span of the chain between the sheaves is unsupported and this would likely deflect under the cutting load. U.S. Pat. No. 1,342,213 (Hanson et al) discloses a chain saw in which an idler wheel is mounted at an outer end of the frame or bar so as to reduce friction of the saw passing around the end. However, the chain passes through a hollow ball which is designed to be located at the center of the tree to provide the fulcrum for swinging the saw. A loop of intermediate chain supports the main saw chain to reduce friction. U.S. Pat. No. 3,872,901 (Bernard) discloses a cutting device having a pair of spaced concentric cutting discs carrying a saw chain therebetween. Each cutting disc has teeth to produce its own kerf, and the chain saw removes material remaining between the kerf so as to produce a single wide cut. It would seem that a very large kerf is produced, with a corresponding large expenditure of energy.